Abstract: A Fabry-Pérot sensor assembly includes an optical element defining a Fabry-Pérot optical cavity therein. A ferrule is affixed to the optical element. The ferrule is configured to physically connect to an optic fiber, aligning the optic fiber optically with the cavity. The optical element includes a MgAl2O4 spinel or aluminum oxynitride Al23N27O5. A method of making an Fabry-Pérot optical cavity includes using a ceramic processing etching process to remove material from a first optical member to form the cavity therein, leaving a rim of the optical member surrounding the cavity peripherally. The method includes affixing a second optical member to the rim to enclose the cavity.

Abstract: In accordance with at least one aspect of this disclosure, a lens is provided. The lens can be used in an imaging platform of a moving platform (e.g., a projectile or guided munition), for example, in a seeker arrangement. The lens can be configured to optical rotation information of the moving platform to an optical sensor as the moving platform moves in space, for example, following a mission profile.

Abstract: A method includes receiving a plurality of laser pulses as a pulse train on a plurality of imaging sensor pixels in an array of pixels. For each pixel in the array of pixels, the method includes receiving a respective one of the laser pulse trains, and scanning the pixels response across a range of frequencies with a bandpass filter to determine pulse shape characteristics of the respective one of the laser pulse trains. The method includes filtering out all of the laser pulse trains that do not fit a predetermined pulse shape characteristic for a true target designation pulse train, and physically adjusting trajectory of a physical resource toward a target based on location on the imaging sensor of one or more pixels receiving a laser pulse train that fits the predetermined pulse shape characteristic for the true target designation pulse train.

Abstract: In accordance with at least one aspect of this disclosure, a dongle for a sensor system can include a pass-through signal carrier configured to allow signals from a sensor discretely associated with the dongle to pass through the dongle to a data concentrator via a first connection, and a non-volatile memory configured to connect to the data concentrator via a second connection. The nonvolatile memory can include calibration data for the sensor that is associated with the dongle.

Abstract: A fluid quantity sensor system for sensing a fluid quantity in a fluid tank can include one or more strain sensors configured to be disposed in physical communication with the tank to sense a strain on one or more portions of the tank. The one or more strain sensors can include at least a first strain sensor disposed in physical communication with a first portion of the tank, and a second strain sensor disposed in physical communication with the second portion of the tank such that the first strain sensor is configured to sense a strain of the first portion of the tank and the second strain sensor is configured to sense a strain of the second portion of the tank. The first strain sensor and the second strain sensor can be positioned such that externally induced stress on a structure forming and/or supporting the tank can be cancelled out such that such that a strain caused by only the fluid in the tank can be determined to determine a weight of the fluid in the tank.

Abstract: In accordance with at least one aspect of this disclosure, a fuel quantity measurement system includes, one or more pressure sensors are configured to operatively connect external to a fuel volume of a fuel tank, and can be operative to sense and output a signal indicative of a pressure outside of the fuel volume. One or more hollow pressure tubes can be configured to be disposed in the fuel volume in the fuel tank. The one or more hollow tubes can have a first end in fluid communication with the fuel volume and a second end configured to be sealed against an ambient environment external to the fuel tank. One or more temperature sensors can be configured to operatively connect within the fuel tank, operative to sense and output a signal indicative of a temperature of the fuel tank.

Abstract: A circuit board assembly can include a circuit component die, a first dielectric layer disposed on a first side of the circuit component die made of a first dielectric material having a high thermal conductivity, a second dielectric layer disposed on a second side of the circuit component die made of the first dielectric material, and a bulk dielectric material having a lower thermal conductivity than the first dielectric material. The bulk dielectric material can have a lower glass transition temperature than the first dielectric material and being heterogeneous to the first dielectric material. The bulk dielectric material can be in flowed contact with lateral sides of the circuit component die, the first dielectric layer, and the second dielectric layer to laterally enclose the circuit component die, the first dielectric layer, and the second dielectric layer.

Abstract: A MEMS accelerometer system can include a proof mass device having a proof mass configured to move from an initial position in response to an input acceleration, a transducer operatively connected to the proof mass device to output a transducer signal correlating to a movement and/or position of the proof mass, a driver operatively connected to the proof mass device and configured to drive the proof mass, and a controller operatively connected to the driver to control the driver. The controller is operatively connected to the transducer to receive the transducer signal and output a drive signal to the driver to drive the proof mass toward an initial position. The system can include an observer module operatively connected to the controller to receive the drive signal. The observer module can be operatively connected to the transducer to receive the transducer signal.

Abstract: A system can include a spinning structure configured to spin in operation, and at least one mass operatively connected to spinning structure to rotate about a spin axis with the spinning structure. The at least one mass can be configured to be moved relative to the spinning structure during a spin of the spinning structure. The system can include an actuation system configured to move the at least one mass relative to the spinning structure. The actuation system can be configured to move the at least one mass while the spinning structure is spinning to use the spin of the spinning structure to induce a precession torque on the spinning structure. The actuation system can be configured to synchronize actuation motion of the at least one mass to the spin of the spinning structure such that the induced precession torque is in a desired direction.

Abstract: In accordance with at least one aspect of this disclosure, a thermoelectric generator (TEG) system can include a TEG conversion element configured to be in thermal communication with a leading edge surface subject to hypersonic flow and a heatsink to generate a temperature differential across the TEG conversion element mounted between the leading edge surface and heatsink, and an electrical conductor configured to connect between the TEG conversion element and a powered unit to supply electrical energy from the TEG conversion element to the powered unit.

Abstract: A method of health monitoring aircraft fuel system structures can include monitoring guided waves emitted by at least one guided wave emitter mounted to an inner hydrogen tank using at least one guided wave detector mounted to the inner hydrogen tank to monitor for a change versus a first baseline. The method can include monitoring guided waves emitted by at least one guided wave emitter mounted to an outer hydrogen tank surrounding the inner hydrogen tank using at least one guided wave detector mounted to the outer tank to monitor for a change versus a second baseline. The method includes outputting an alert to at least one of aircraft avionics and/or an onboard integrated Vehicle Health Management system (IVHM) if a change versus either or both of the first or second baselines is detected.

Abstract: A system includes an aircraft fuel tank defining an interior configured to store fuel for flight. The interior is defined by a plurality of tank walls including a vertical wing spar of a wing. An opening is defined through the vertical wing spar. A guide tube has a first end sealingly engaged in the opening of the vertical wing spar to prevent leakage between the guide tube and the opening. An optic fiber extends through the guide tube, sealingly engaged to the first end of the guide tube to prevent leakage between the optic fiber and the first end of the guide tube. An optical pressure sensor is optically coupled to the optic fiber proximate a second end of the guide tube opposite the first end.

Abstract: A method of controlling an actuator includes transmitting a drive signal to an actuator motor to move a device, including automatically compensating for and rejecting uncertain and unmodeled torque disturbances of the actuator motor. A controller for an actuator includes a processing device configured to transmit a drive signal to an actuator motor to move a device, including automatically compensating for and rejecting uncertain and unmodeled torque disturbances of the actuator motor to perform the method.

Abstract: An optical sensor includes an optic fiber optically coupled to a cavity. An optical path is defined from the fiber, across the cavity, and reflected back across the cavity back into the fiber. The cavity is an open cavity that is in fluid communication with an environment ambient to the cavity for detection of changes in index of refraction inside the cavity due to whether the environment ambient to the cavity is gaseous or liquid.

Abstract: A thermo-optic coefficient measurement system can include a housing structure configured to retain at least a first plate sample, a second plate sample, and a third plate sample in a stacked, alternating stagger arrangement such that a gap exists between the first plate sample and the third plate sample that is the thickness of the second plate sample. The system can also include a first optical device connected to the housing to output a first laser configured to be coincident with the first plate sample and the third plate sample. The first optical device can be configured to receive a first return signal. The system can also include a second optical device connected to the housing to output a second laser configured to be coincident with the second plate sample, the second optical device can be configured to receive a second return signal.

Abstract: A Fabry-Pérot sensor assembly includes an optical element defining a Fabry-Pérot optical cavity therein. A sensor ferrule is affixed to the optical element. The sensor ferrule is configured to physically connect to an optical fiber, optically aligning and spacing the optical fiber with the optical cavity. The sensor ferrule defines a bore for receiving the optical fiber. The bore extends along a longitudinal axis that extends to the optical element. The optical cavity is a second optical member defined between a first optical member and a third optical member spaced apart from the first optical member along the longitudinal axis. The first optical member includes a curved lens surface facing away from the optical cavity and into the bore, configured to collimate light passing through the first optical member.

Abstract: A liquid level sensing system includes a sensing probe including an axial guided wave (AGW) transducer, the AGW transducer including a sensing element, and a rod operatively associated with the AGW transducer, the AGW transducer operatively connected to a first end of the rod. The liquid level sensing systems includes a liquid tank, such that a second end of the rod extends through an opening in an inner wall of the liquid tank into the liquid tank, the first end of the rod and the AGW transducer being outside of the inner wall of the liquid-hydrogen tank.

Abstract: A Fabry-Pérot sensor assembly includes an optical element defining a Fabry-Pérot optical cavity therein. A sensor ferrule is affixed to the optical element. The sensor ferrule is configured to physically connect to an optical fiber, aligning the optical fiber optically with the cavity. The optical element includes a LaGd doped hafnium or zirconium oxide ceramic or Nd:YAG ceramic or single crystals.

Abstract: A Fabry-Pérot sensor assembly includes an optical element defining a Fabry-Pérot optical cavity therein. A sensor ferrule is affixed to the optical element. The sensor ferrule is configured to physically connect to an optical fiber, optically aligning and spacing the optical fiber with the optical cavity. The sensor ferrule defines a bore for receiving the optical fiber. The bore extends along a longitudinal axis that extends to the optical element. The optical cavity is a second optical member defined between a first optical member and a third optical member spaced apart from the first optical member along the longitudinal axis. At least one of the first optical member and the third optical member includes a radiused surface bounding the optical cavity and spanning across the optical cavity laterally relative to the longitudinal axis.

Abstract: A laser diode drive system configured to output a drive signal to control a voltage provided to a laser diode can include a circuit sensor system configured to output a sensed signal indicative of a drive current of a laser diode, and a temperature sensor configured to output a temperature signal indicative of a temperature of the laser diode or an ambient temperature of the laser diode. The system can include a temperature compensation system configured to output a correction signal based on the temperature signal to compensate for a temperature dependent factor in the sensed signal.